Anchor elements

Abstract

A method of making on site a ground anchor having at least double corrosion protection about the anchor element, comprises locating a number of fixed lengths of corrosion proof sleeve about the element, applying a cap to the sleeve at the end of the element, and supplying a self-setting composition into the sleeve via the cap to fill an annular clearance between the sleeve and the element. The cap may be left in place on the end of the anchor to protect the anchor during insertion thereof into a borehole. The sleeve preferably comprises an outer plastics layer, an inner metal layer, and an intermediate layer of set filler.

I claim: 
     
       1. A method of at least double corrosion proofing an anchor element on site outside a hole in a substrate, in which hole the anchor is to be installed, comprising (i) at the site locating a sufficient number of lengths of corrosion proof sleeve in end-to-end relation about an end portion of the anchor element to cover the length of the element to be corrosion proofed while the element is outside the hole,   (ii) applying a cap to the sleeve at the end of the anchor element, the cap having an inlet for self-setting composition, and being secured to the anchor element,   (iii) supplying a self-setting composition through the inlet, via the cap, into an annular clearance between the element and the sleeve there to set to secure the sleeve to the element,   (iv) locating the formed corrosion proofed anchor element in the hole in the substrate and   (v) grouting the element in the hole.   
     
     
       2. A method according to claim 1, in which the cap is secured to the anchor element by means of the self-setting composition. 
     
     
       3. A method according to claim 1 in which the sleeved anchor element is upwardly inclined away from the cap whilst the self-setting composition is supplied into the sleeve. 
     
     
       4. A method according to claim 1, in which the inlet is located in the side of the cap. 
     
     
       5. A method according to claim 1, in which the sleeve has at least two corrosion-proof layers. 
     
     
       6. A method according to claim 5, in which the sleeve comprises three layers, the intermediate layer being of set filler and at least one of the other two layers being of plastics. 
     
     
       7. A method according to claim 6, in which the sleeve comprises an outer layer of plastics, an intermediate layer of set filler and an inner layer of metal. 
     
     
       8. A method according to claim 1, in which the anchor element is a bar having a plain or a ribbed profile. 
     
     
       9. A method according to claim 1, in which the anchor element is a strand tendon. 
     
     
       10. An anchor, comprising an anchor element, a plurality of sleeve lengths being located in end-to-end relation about an end portion of the element, the sleeve lengths being secured to the element by means of a self-setting composition located between the element and the sleeve, the sleeve comprising an outer layer of plastics having external castellations, an intermediate layer of set filler and an inner layer of metal being internally threaded, and a cap being secured to an end of the anchor by means of a self-setting composition. 
     
     
       11. A sleeve for use in the anchor of claim 10, comprising an outer layer of plastics and an inner layer of metal. 
     
     
       12. A sleeve according to claim 11, which includes an intermediate layer of set filler. 
     
     
       13. A sleeve according to claim 11 in which the sleeve has longitudinally spaced apart external circumferential ribs. 
     
     
       14. A sleeve according to claim 11 in which the sleeve is internally threaded.